4.2.2 - Evolution and classification part 2 Flashcards
(75 cards)
1
Q
What is evolution ?
A
Evolution is the theory that describes the way in which organisms evolve, or change, over many many years
2
Q
Give 4 sources of evidence for evolution
A
- Palaeontology (fossils)
- Comparative anatomy
- Comparative biochemistry
- Comparative embryology
3
Q
How can the relative age of fossils be determined?
A
- Over time sediment is deposited to form rock strata
- Recent rock strata are found at the top and older rock strata are found at the bottom
- Radioisotope dating can be completed on fossils to date rock strata
4
Q
How do fossils provide evidence for evolution?
A
- Fossils of the simplest organisms are found in the oldest rocks
- Fossils of more complex organisms are found in more recent rocks
- Allow relationships between extinct and living organisms to be investigated
- Sequence in which organisms are found matches ecological links
5
Q
What is comparative anatomy?
A
The study of similarities and differences between organisms’ anatomy
6
Q
How does comparative anatomy provide evidence for evolution?
A
Homologous structures provide evidence for divergent evolution and that from a common ancestor different species have evolved
7
Q
What are homologous structures?
A
A structure which appears superficially different (and may perform different functions) in different organisms but has the same underlying structure
8
Q
What is divergent evolution?
A
Species diverge over time into two different species, resulting in new species becoming less like the old one
9
Q
What is comparative biochemistry?
A
Similarities and differences between the chemical make up of organisms
10
Q
How does comparative biochemistry provide evidence for evolution?
A
- Molecules change over time
- Some important molecules are highly conserved among species
- Slight changes that do occur in these molecules can help identify evolutionary links
11
Q
How does comparative embryology provide evidence for evolution?
A
- Embryos of different animals looks very similar
- Shows animals develop in a similar way
- Implies the process of embryonic development has a common origin
12
Q
What is variation?
A
Differences in characteristics or genes within or between species
13
Q
Define intraspecific variation
A
Differences between individuals within the same species
14
Q
Define interspecific variation
A
Differences between different species
15
Q
What are the 2 causes of variation?
A
Environment and genetics
16
Q
Are environmental effects heritable?
A
No
17
Q
Give 2 examples of environmental effects
A
- Hair dye
- Diet
18
Q
Are genetic factors heritable?
A
Yes
19
Q
What are the 5 causes of genetic variation?
A
- Presence of a different allele
- Random fertilisation/random fusion of gametes
- Random mating
- Meiosis
- Mutations
20
Q
What are the two types of mutations?
A
Point mutations and chromosomal mutations
21
Q
What are point mutations?
A
Change in the base sequence of DNA
22
Q
How do chromosomal mutations arise?
A
From crossing over
23
Q
What are the two sources of variation in meiosis?
A
- Crossing over
- Independent assortment
24
Q
What are the two types of variation?
A
Continuous and discontinuous
25
What is continuous variation?
- Variation of all possible intermediate values between the two extremes
- it can be plotted to give a normal distribution curve
26
Give 2 examples of continuous variation
Height
| Weight
27
What is discontinuous variation?
- discrete groupings of individuals
| - presented as a bar chart
28
Give an example of discontinuous variation
Blood group
29
Why does continuous variation occur?
-due to the inheritance of 2 or more genes
30
Why does discontinuous variation occur?
Result of inheritance of one gene with 2 or more alleles
31
Is continuous variation influenced by the environment?
It can be
32
Is discontinuous variation influenced by the environment?
No
33
Define polygenic
A characteristic is controlled by two or more genes
34
Define multifactorial
Involving both genetic and environmental factors
35
Outline the process of natural selection
- populations show a wide range of variation
- population is exposed to a selection pressure
- organisms with a characteristic enables them to survive the selection pressure have an advantage
- they survive and reproduce
- organisms that survive possess an allele giving them the advantageous characteristic
- offspring gain the survival advantage
- frequency of the advantageous allele increases
36
What are the 4 characteristics of a normal distribution curve?
- unimodal
- asymptotic
- symmetrical
- mean, median, and mode are all equal
37
What is standard deviation?
A measure of spread of data around the mean
38
What is the student's t test used for?
To compare 2 sets of numerical data
39
When is the unpaired t test used?
To compare data from different individuals
40
When is the paired t test used?
To compare data from the same individual
41
When is Spearman's rank correlation coefficient used?
To determine if there is a correlation between two variables
42
Define adaptation
Characteristics that increase an organism's chance of survival and reproduction in its environment
43
What are the 3 types of adaptations?
- anatomical
- behavioural
-physiological
44
What are anatomical adaptations?
Adaptations relating to physical features, both internal and external
45
Give 4 examples of anatomical adaptions
- Camouflage
- Teeth i.e. shape and type are related to diet
- Mimicry
- Body Covering i.e. scales, feathers, fur
46
What are behavioural adaptations?
Adaptations relating to the way an organism acts
47
What are the 2 types of behavioural adaptations?
Innate and learned
48
What is an innate behavioural adaption?
The ability to do the behaviour is inherited through genes
49
Give an example of 2 innate adaptions
- spiders building webs
| - caterpillars building cocoons
50
What is a learned behaviour adaptation?
a behaviour that is learnt from experience or observation
51
Give 2 examples of learned adatations
- use of tools
| - playing dead
52
What are physiological adaptations?
Adaptations relating to processes that take place within an organism
53
Give 4 examples of physiological adaptations
- Poison production in reptiles and plants
- Antibiotic production to kill competing bacteria
- water holding better adapted for dry conditions
- blinking
54
Define analogous structure
Structures which have adapted to perform the same function but have different (genetic) origins
55
Define convergent evolution
Organisms evolve similarities because the organisms adapt to similar environments or other selection processes
56
Why do organisms from different taxonomic groups show similar structures?
-they adapt to similar environments or other selection pressures
57
Give an example of two sets of organisms from different taxonomic groups that are similar
Marsupials and placental mammals in Australia
58
Define allele frequency
How many alleles of a particular type are found in the total number of possible alleles for that gene
59
Define gene pool
All genes and their allelic forms in a given population
60
Define selection pressure
Any factor for which there is competition between individuals in which some will survive and some will die
61
Define selectively neutral gene
an allele not involved in the selection of individuals
62
Define advantageous allele
An allele which provides an individual with a survival advantage
63
Define advantageous characterisitc
A characteristic which arises from an advantageous allele, which provides an individual with a survival advantage
64
Define natural selection
The process by which organisms best suited to their environment survive and reproduce, passing on their characteristics to their offspring through their genes
65
Describe the effect of the industrial revolution on peppered moths
- before the industrial revolution peppered moths were light in colour
- after the industrial revolution peppered moths became darker
- soot caused the bark of trees to get darker
- dark colour moths were better camouflaged
- light moths were eaten
66
What was the effect of the industrial revolution on the allele frequency for black wings in peppered moths?
The alleles frequency increased
67
What characteristics increase the ability of a population to survive a change in the environment?
- having a large gene pool means a population is likely to evolve and tolerate change in environment
- because the population is more likely to have some individuals with advantageous characteristics who will survive
68
Give 3 organisms which human activity has affected the populations
- blowflies
- MRSA
-flavobacterium
69
How have humans affected Staph. A?
-use of antibiotics has led to bacteria developing resistance
70
What is phylogeny ?
It is the name given to the evolutionary relationships between organisms.
71
Define phylogenetics
The study if the evolutionary history of groups of organisms
72
What does phylogeny reveal ?
Which group a particular organism is related to and how closely they are related
73
What is a phylogenetic tree ?
It is a diagram used to represent the evolutionary relationships between organisms
74
What does a phylogenetic tree show ?
It shows that different species have evolved from a common ancestor
75
What are the advantages of phylogenetic classification ?
- It allows classification to confirm the groups are correct or causes them to be changed
- Phylogeny produces a continuous tree whereas classification requires discrete groups
- Binomial nomenclature can be misleading as it implies that different groups within the same ranks are equivalent
